[roll third_party/pigweed] pw_docgen: Remove "MKDIR" prints

The MKDIR prints during docgen produce a lot of noise when there are
issues with Sphinx. Docgen itself has been reliable, so these prints
aren't needed for debugging. Remove them to clean up the build output.

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/52560

third_party/pigweed Rolled-Commits: 121de17f0f6fcd8..80a1f2fee52f567
Roller-URL: https://ci.chromium.org/b/8842161610885337376
Cq-Cl-Tag: roller-builder:pigweed-experimental-roller
Cq-Cl-Tag: roller-bid:8842161610885337376
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I730f5deec907aaae1c3b00463bb05d5b8604f722
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/52580
Reviewed-by: Pigweed Integration Roller <pigweed-integration-roller@pigweed.google.com.iam.gserviceaccount.com>
Commit-Queue: Pigweed Integration Roller <pigweed-integration-roller@pigweed.google.com.iam.gserviceaccount.com>
diff --git a/third_party/pigweed b/third_party/pigweed
index 121de17..80a1f2f 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 121de17f0f6fcd89be45a22a71f3579919f5753d
+Subproject commit 80a1f2fee52f56736a1c45a0a63a37cd43508db8